brucellosis

Brucellosis: description

Brucellosis is a bacterial infectious disease that affects humans and animals alike (anthropozoonosis). It is usually transmitted from animals to humans.

A brucellosis can be triggered by various bacteria. Depending on the pathogen, a distinction is made between different types of brucellosis, for example Mediterranean fever (undulating fever), Bang’s disease and pig and dog brucellosis.

In humans, the Mediterranean fever is most common, pig and dog brucellosis are very rare.

The symptoms of brucellosis can be very different. In about 90 percent of cases, there are no signs of infection. In the remaining ten percent, symptoms vary from nonspecific signs of inflammation such as fever or headache to severe organ damage.

What happens with brucellosis?

The pathogens of brucellosis enter the human body via the mucous membranes or minor lesions in the skin. After penetration, they are transported by cells of the immune system to the nearest lymph node. There they can get from the lymph into the blood stream and on to various organs (such as the spleen, liver) or into the bone marrow, where they cause inflammation.

Brucellosis: facts and figures

Every year around 40 new cases of brucellosis are reported in Germany. Doctors from around 500,000 sufferers worldwide go out.

Most of the patients in Germany have contracted brucellosis when traveling abroad. Particularly widespread are the pathogens in the Mediterranean countries.

In Germany, according to the Infection Protection Act (IfSG), there is a duty to report brucellosis. This means that the suspect, actual illness and death from brucellosis must be reported by the doctor to the health department. Diseased animals are also notifiable. The total stock of animals that could become infected (cattle, goats, sheep, horses, pigs, dogs) in Germany is officially brucellosis free. Diseased animals are usually imported from abroad. Occasionally it comes to outbreaks in pigs in free range, which have infected with wild boar.

incubation period

The time between the infection and the outbreak of brucellosis (incubation period) is very variable: it can only last for five days, but can be more than two years. On average, the incubation period is about four months, in Bang’s disease usually only one to three weeks.

The pathogens can be passed on to other people throughout the incubation period.

Brucellosis: symptoms

In about 90 percent of all those affected brucellosis runs without or only with mild symptoms (subclinical course). The fact that a brucellosis is actually present, the doctor can then only detect evidence of antibodies against the pathogens (antibodies) in the blood.

In the other ten percent of cases, the condition is either acute or chronic. This shows different symptoms:

Acute brucellosis

Acute brucellosis can begin creepingly or suddenly. An insidious course usually occurs in Bang’s disease, a sudden onset of Mediterranean fever. First symptoms are non-specific signs of illness such as:

• fever
• nausea
• fatigue
• Headache and body aches
• night sweats

In acute brucellosis, the fever may last for one to three weeks. Especially in Mediterranean fever, two- to five-day fever breaks often occur. Such a course is called undulating fever.

A slow heartbeat (bradycardia) and visibly swollen lymph nodes are also symptoms of acute brucellosis.

Chronic brucellosis

If brucellosis is not recognized and treated, chronic brucellosis may develop after the onset of acute symptoms. A chronic course occurs in about five percent of cases. General symptoms are:

• reduced efficiency
• sweats
• depressive phases

In addition, there are usually permanent sites of inflammation in the liver, spleen or the bones. If the bone marrow is affected, the blood formation is disturbed as a result.

Furthermore, brucellosis can cause chronic inflammation of various organs and tissues. This includes:

• the meninges (meningitis)
• the heart lining (endocarditis)
• Testes (orchitis) and epididymis (epididymitis)
• Gallbladder (cholecystitis)
• Pancreas (pancreatitis)
• Peritoneum (peritonitis)
• Lung (pneumonia)
• Vertebral body (spondylitis)
• Eyes (Uveitis)

Rarely, there is an enlargement of the liver and spleen (hepatosplenomegaly).

Brucellosis: causes and risk factors

The triggers of brucellosis are small, gram-negative bacillus bacteria of the genus Brucella, the so-called Brucelles. Depending on the triggering Brucellen type, the following forms of brucellosis are distinguished:

• Mediterranean or Malta fever: the causative agent is Brucella melitensis (mainly goats, sheep and camels)
• Bang’s disease, Bang’s disease: caused by Brucella abortus (mainly in cattle)
• Pigs Brucellosis: by Brucella suis
• Dog brucellosis: by Brucella canis

The last two Brucella species and the causative organisms Brucella ovis and Brucella neotomae are extremely rare in humans.

Contagion from animals and food

Infection of humans usually occurs through contact with infected animals (especially their faeces and urine) and through the consumption of infected raw meat or other uncooked or unpasteurised animal products such as milk or cheese. In Germany, all animals are officially brucellosis free. The infection is therefore usually abroad, where brucellosis with regional differences is still widespread.

Travelers to the Mediterranean should be aware that domestic animals and farm animals such as goats, sheep and pigs are often infected with the Mediterranean fever. The pork brucellosis occurs mainly in North America, Bang’s disease mainly in the cattle breeding areas of the tropical zone.

Farmers, veterinarians and laboratory staff are among the occupationally exposed risk groups.

Contagion from person to person

In rare cases, transmission takes place directly from person to person. Infected mothers can pass on brucellosis agents to their children via breast milk. Bone marrow transplants, blood transfusions, and intercourse have rarely been linked to brucellosis in the past.

Brucellosis: examinations and diagnosis

The diagnosis of brucellosis is very difficult, as each disease has different or no symptoms at all. In addition, other diseases that cause the same non-specific signs of inflammation must be excluded in the diagnosis.

First, the medical history (anamnesis) is inquired during the examination. This will give the doctor possible evidence of brucellosis.

If there is a suspicion, a blood test will be carried out in the laboratory. In blood serum, specific antibodies (antibodies) against the pathogen can be detected in the case of an infection.

Depending on where the body shows signs of inflammation, brucellosis agents can also be detected in other tissues and fluids. These include, for example, cerebrospinal fluid (CSF), urine, liver, spleen and bone marrow.

The evaluation of the (blood) tests takes several days.

Brucellosis: treatment

If there is a reasonable suspicion of brucellosis therapy must be started immediately.

As a rule, brucellosis is treated with a combination of different antibiotics. In an acute course, doxycycline is administered for six weeks and streptomycin or rifampicin for two to three weeks. In a chronic course, the antibiotic therapy extended to up to six months. The success of the therapy is monitored by regular blood tests.

If the brucellosis pathogens have already attacked internal organs, the therapy is also prolonged.

In cases of infestation of the nervous system (neurobrucellosis) or infestation of the heart’s lining (inflammation of the heart lining = endocarditis), other medicines may also be prescribed, usually antibiotics such as amoxicillin and chloramphenicol.

In rare cases, brucellosis agents infect the bones or heart valves, possibly requiring surgery.

In children under the age of nine and pregnant women, cotrimoxazole is given in combination with rifampicin for a period of six weeks for the treatment of brucellosis.

Herxheimer reaction

In antibiotic therapy, the pathogens disintegrate. As a result, many inflammation messengers are distributed in a relatively short time. The body responds with symptoms such as fever and chills or with an exacerbation of the original symptoms. Headache and body aches, fatigue, difficulty concentrating and depression can also occur. This body reaction is called the Herxheimer reaction. It can vary in severity with each patient, but is a normal part of the therapy and not an aggravation of the disease.

Brucellosis: prevention

A vaccine against brucellosis is not yet possible in humans. In the foreground is therefore the fight against the pathogen in the animals. In Germany, all animals are officially brucellosis free according to the so-called brucellosis regulation. This is not true for many other countries.

Therefore, avoid consuming raw meat in countries where the pathogen is still prevalent (endemic areas). Drink only boiled milk and eat only cheese and other milk products from pasteurized milk.

In addition, avoid contact with animals in endemic areas.

Persons with a lot of work related to animals should thoroughly clean and disinfect their hands after each contact and change their clothes. Veterinarians are advised to wear gloves and use a skin-protecting cream when performing surgery.

At brucellosis ill women are not allowed to breastfeed; their milk may be given to the child when boiled.

Brucellosis: disease course and prognosis

Disease course and prognosis in brucellosis are different in each patient. Depending on the type of pathogen, the severity of the disease and the stage at which brucellosis is diagnosed, a very individual prognosis results for each affected person.

If therapy starts too late, undulating fever can become chronic and last up to 20 years. Chronic brucellosis occurs in about five percent of all patients after the onset of acute symptoms. If a brucellosis is not treated properly, the relapse frequency (recurrence rate) is very high; This means that it can suddenly come back to fevers after years.

On average, about two percent of all those affected die from brucellosis. Deaths occur mainly in patients with Mediterranean fever, in which, if the disease goes unnoticed and untreated for a long time, can develop inflammation of the endocarditis (endocarditis).

Will one brucellosis Recognized early and treated consistently, the prognosis is favorable and sufferers can usually be cured completely.